There has been known a device adapted to assist a walker with his/her walking by imparting torques about leg joints (hip joints, knee joints, and foot joints) to the walker.
In the walking assist device, if a walking assist rhythm (a rhythm for imparting torque to a walker) is programmed beforehand, then the walker is forced to follow the walking rhythm based on the programmed walking assist rhythm. Therefore, if the walking assist rhythm is slow, then the walker has to walk slowly even if the walker wishes to walk faster. Conversely, if the walking assist rhythm is fast, then the walker has to walk fast even if the walker wishes to walk slowly. Hence, the walker is very likely to develop uncomfortableness, feeling that the walker is forced to walk in a manner against his/her will.
A walking assist rhythm arranged to fully follow a walking rhythm of a walker enables the walker to walk at a walking rhythm based on his/her own will.
In other words, if the walking assist rhythm is controlled to be faster in response to a change in the movement of legs when the walker moves his/her legs faster, speeding up the walking rhythm, then the walker will be able to walk faster as he/she intends to. Similarly, if the walking assist rhythm is controlled to be slower in response to a change in the movement of the legs when the walker moves his/her legs slowly, slowing down the walking rhythm, then the walker will be able to walk slowly as he/she intends to.
On the other hand, it is important for a walker wearing the walking assist device to feel that his/her walking is assisted since he/she is using the walking assist device. Hence, in walking assistance fully led by a walker, the walker may feel uncomfortable with the walk using the walking assist device due to such feeling of not being assisted, even if the walker can walk at an intended rhythm.
If a walking rhythm generated by a walker himself/herself suddenly changes or if the walking rhythm is unnatural from normal walk, then the walking based on the walking rhythm is furthered, possibly leading to an increase in burden to the mind and body of the walker.
Accordingly, the present invention is intended to achieve a solution by providing a system capable of controlling an autonomous walking assist rhythm, while following changes in a walking rhythm of a walker at the same time.